Fuel-injection system for an internal combustion engine

ABSTRACT

The invention relates to a fuel-injection system for an internal combustion engine. The fuel-injection system contains a number of fuel injectors which are supplied with fuel by a high-pressure pump via a common inlet pipe and high-pressure lines leading from said pump to the individual fuel injectors. High-pressure storage devices are provided in each of the high-pressure lines in each of the high-pressure lines, the fuel storage volumes of said high-pressure storage devices being between 80 and 300 times, preferably between 120 and 200 times the maximum injection quantity per injection action. The diameter D 2  of the high-pressure lines leading from the common inlet pipe to the high-pressure storage devices is measured to minimize the difference in the quantities of fuel injected by the fuel injectors.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a fuel injection system for aninternal-combustion engine particularly a diesel engine, which containsa number of fuel injectors for injecting fuel into the combustion spacesof the internal-combustion engine and a high-pressure pump whichsupplies the fuel injectors with fuel by way of a common inflow pipe andhigh-pressure lines leading to the individual fuel injectors, as well ashigh-pressure storage devices which have a defined fuel storage volumeand are provided in the high-pressure lines leading to the fuelinjectors.

In the case of internal-combustion engines, particularly large-volumediesel engines, fuel injection systems are increasingly used in whichfuel is supplied from a fuel supply by means of a high-pressure pump byway of a high-pressure line into a high-pressure storage device. Fromthe high-pressure storage device acting as an oil-elastic storagedevice, the fuel is supplied by way of additional high-pressure lines tofuel injectors which inject the fuel during injection operations intothe combustion spaces of the internal-combustion engine. So far, thehigh-pressure storage device has predominantly been provided in the formof a so-called common rail which is a tube-shaped elongated element fromwhich the high-pressure lines branch off which supply the individualfuel injectors. Furthermore, fuel injection systems are known in thecase of which, in addition to or instead of such a common high-pressurestorage device in the form of a common rail, high-pressure storagedevices are provided as individual storage devices separately for eachfuel injector.

Fuel injection systems, in the case of which, in addition to a commonhigh-pressure storage device, one individual storage device respectivelyis provided separately for each fuel injector are known from GermanPatent Documents 43 41 543 A1 and DE 43 41 546 A1. In the case of thefuel injection system known from the former document, a parallelswitching device consisting of a return valve, which is interconnectedin the fuel conveying direction, and of a throttle is provided in thehigh-pressure line leading from the common high-pressure storage deviceto the high-pressure storage device provided separately for each fuelinjector, the system prevents an uncontrolled flowing-back of fuel fromthe separate high-pressure storage device into the common high-pressurestorage device and prevents an influencing of the pressure in theseparate pressure storage spaces of the other fuel injectors, while tothe return valve permits a rapid refilling of the separate high-pressurestorage devices from the common high-pressure storage device. Suchmeasures for avoiding the mutual influencing of the pressure in theseparate high-pressure storage devices are not provided in the case ofthe fuel injection system known from the second document.

Furthermore, a fuel injection system is known from German PatentDocument DE 43 44 190 A1, in which fuel is fed under a high pressure tohigh-pressure storage devices separately provided for each fuel injectorfrom a fuel supply by way of high-pressure lines by means of ahigh-pressure pump. A shut-off valve is connected into eachhigh-pressure line connecting a fuel injector with the assignedhigh-pressure storage device, which shut-off valve has the purpose oflimiting the fuel quantity flowing through during a pressure intervalwhich is characterized by the pressure drop occurring with the injectionoperation or in the case of a leakage. However, measures are notindicated by means of which the mutual influencing of the pressure inthe individual high-pressure storage devices is to be avoided.

It is an object of the invention to provide an improved fuel injectionsystem for an internal-combustion engine.

According to the invention, a fuel injection system for aninternal-combustion engine, particularly a diesel engine, is providedwhich contains a number of fuel injectors for injecting fuel into thecombustion spaces of the internal-combustion engine as well as ahigh-pressure pump which supplies fuel to the fuel injectors by way of acommon inlet pipe and to high-pressure lines leading to the individualfuel injectors. In the high-pressure lines leading to the fuelinjectors, high-pressure storage devices are provided which each have adefined fuel storage volume. According to the invention, it is providedthat the fuel storage volume of each high-pressure storage deviceamounts to between 80 and 300 times, preferably between 120 and 200times the maximal injection quantity per injection operation, and thatthe diameter D₂ of the high-pressure lines leading from the common inletpipe to the high-pressure storage devices is dimensioned such that thedifference in the quantities injected by the fuel injectors assumes aminimum.

The invention is essentially based on the recognition that a variationof the diameter D₂ of the high-pressure lines leading from the commoninlet pipe to the high-pressure storage devices results already within arelatively small range in a significant change of the difference in thequantities injected by the individual fuel injectors and has apronounced minimum in the range of the optimal diameter. By using thisminimum, the fuel injection system can be designed such that thedifference in the injected quantities is minimal and uniform ignitionpressures can be achieved from one cylinder to the next. The minimum ofthe difference in the injected quantities indicates that the mutualinfluence of the individual pressure storage spaces also has a minimum.

A significant advantage of the fuel injection system according to theinvention is the fact that the high-pressure lines supplying theindividual high-pressure storage devices can have a small diameter andare therefore easy to bend and mount. It is another advantage that, forminimizing the mutual influencing of the individual high-pressurestorage devices, no additional elements, such as return valves, arerequired. For example, because of the inertia of masses of the movedparts, valves have a delayed response behavior so that the propagationof pressure disturbances and the mutual influencing of the injectorscannot be prevented thereby. Since, in the case of the injection systemaccording to the invention, the high-pressure lines supplying theindividual high-pressure storage devices exercise a throttling effect onthe fuel flowing through, a self-protection of the internal-combustionengine continues to exist against an overspeed because, in the event ofthe occurrence of such an overspeed, the high-pressure storage devicesare being no longer completely filled.

It is preferably provided that the diameter D₂ of the high-pressurelines leading from the common inlet pipe to the high-pressure storagedevices meets the following requirement:

D₂≈((4×(V_(E)+V_(L)))/cg₂×π×T_(ASP)))^(½)

wherein

V_(E) is the maximal injection volume per injection operation,

V_(L) is a control and leakage quantity per injection operation possiblyoccurring at the fuel injector,

cg₂ is a standard value for the fuel flow rate in the line,

T_(ASP) is the time duration for an operating cycle of theinternal-combustion engine; wherein the values for V_(E), V_(L) andT_(ASP) are defined by the layout of the internal-combustion engine, andcg₂ is to amount to between 5 and 50 m/s. In the case of long thinlines, the value for cg₂ is between 5 and 25 m/s, and preferably between7 and 9 m/s. In the case of short lines or throttle-type transitions,the value for cg₂ is between 10 and 50 m/s, preferably between 35 and 45m/s. As a result, the optimal value for the diameter D₂ can bemathematically determined already during the layout of theinternal-combustion engine. However, it is advantageous to determine bymeans of a variation of the diameter D₂ about the thus obtained valuethe value for the diameter D₂ of the high-pressure lines in practicaltests, in the case of which diameter the difference in the quantitiesinjected by the fuel injectors is in fact minimal, as explained above.

According to a further development of the invention, it is provided todetermine the diameter D₄ of the high-pressure lines leading from thehigh-pressure storage devices to the fuel injectors to be at least solarge that the flow rate cg₄ of the fuel in these high-pressure linesduring the injection operation is no higher than 30 m/s, preferably nohigher than 25 m/s.

Preferably, it is provided that the diameter D₄ of the high-pressurelines leading from the high-pressure storage devices to the fuelinjectors meets the following requirement:

D₄≧((4×V_(E))/(cg₄×π×SD))^(½)

wherein

V_(E) is the maximal injection volume per injection operation,

cg₄ is the permissible maximal flow rate of the fuel in the highpressure line 4, and

SD is the duration of the injection operation.

According to another advantageous further development of the invention,it is provided that the following applies to the diameters D₁ of thecommon inlet pipe and D₂ of the high-pressure lines leading from thecommon inlet pipe to the high-pressure storage devices:

D₁ ≧n _(R) ^(½)×D₂

wherein n_(R) is the number of fuel injectors 5 connected to the commoninlet pipe 1.

It is advantageously provided that the lengths of the high-pressurelines leading from the common inflow pipe to the high-pressure storagedevices are identical. As a result, it is to be ensured that the mutualinfluencing of the individual high-pressure storage devices is the samefor all fuel injectors. Other objects, advantages and novel features ofthe present invention will become apparent from the following detaileddescription of the invention when considered in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

It is particularly advantageous to coordinate the diameter and thelength of the common inflow pipe and of the high-pressure lines leadingfrom the common inflow pipe to the high-pressure storage device withrespect to one another such that the dynamic flow resistance of the feedpipes for all fuel injectors is the same. By taking into account thediameter and the length of the common inflow pipe when determining theflow resistance in the feed pipes, it is achieved that the sameconditions exist for the supply of all fuel injectors.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following, an embodiment of the invention will be explained bymeans of the drawing.

FIG. 1 is a schematic block diagram of a fuel injection system accordingto an embodiment of the invention; and

FIG. 2 is a diagram which reflects the dependence of the difference inquantities injected by the individual fuel injectors with respect to oneanother on the diameter of the high-pressure lines supplying thehigh-pressure storage devices assigned to the individual fuel injectors.

The fuel injection system illustrated in FIG. 1 contains a number offuel injectors 5 for injecting fuel into the combustion spaces of ainternal-combustion engine, particularly a diesel engine. The fuelinjectors 5 are controlled by means of a control unit, which is notillustrated separately in FIG. 1, in such a manner that a fuel quantitywhich is optimally adapted to the rotational speed and the loadcondition of the internal-combustion engine is injected into thecombustion spaces of the internal-combustion engine. From a fuel supply,which is also not separately illustrated in FIG. 1, the fuel is firstfed by means of one or several high-pressure pumps 6 to a common inflowpipe 1, from which high-pressure lines 2, 4 branch off which are usedfor supplying the individual fuel injectors 5. In the embodimentillustrated in FIG. 1, two inflow pipes 1 are provided which each supplyfour fuel injectors 5 jointly, as in the case of an 8V diesel engine.

In the high-pressure lines 2, 4 leading to the fuel injectors 5,high-pressure storage devices 3 are provided, specifically onerespectively for each fuel injector 5. The portion of the high-pressureline leading from the common inflow pipe 1 to the high-pressure storagedevice 3 has the reference number 2; whereas the portion of thehigh-pressure line leading from the high pressure storage device 3 tothe fuel injector 5 has the reference number 4.

The high-pressure storage devices 3 act as oil-elastic storage devicesin whose fuel storage volume fuel, which is acted upon by the highpressure supplied by the high-pressure pump 6, is stored for the feedingto the fuel injectors 5. The fuel storage volume of each of thehigh-pressure storage devices 3 amounts to between 80 and 300 times,preferably between 120 and 200 times the maximal quantity of the fuel tobe injected during each injection operation by a fuel injector 5 intothe assigned combustion space of the internal-combustion engine.

The diameter D₂ of the portion 2 of the high-pressure line leading fromthe common inflow pipe 1 to the high-pressure storage device 3 isdimensioned such that the difference in the quantities injected by thefuel injectors assumes a minimum at the nominal rotational speed of theinternal-combustion engine.

The diagram illustrated in FIG. 2 shows the maximal difference in thequantities injected by the individual fuel injectors; thus, thedifference in the injected quantities from one cylinder of theinternal-combustion engine to the next. During the implemented tests andcalculations, the diameter D₂ of the high-pressure lines 2 leading fromthe common inflow pipe 1 to the high-pressure storage devices 3 wasvaried between 1.0 and 5.0 mm; in the range of 1.0 to 3.5 mm, in stepsof 0.5 mm; and then in a further step of 1.5 mm. As illustrated, thedifference in injected quantities in the range of from 1.5 to 2.5 mmwith values of between 0.25 to 0.35% has a minimum, whose concentrationis at a diameter D₂ of 2.0 mm, but shows no local maximum there, which,however, will not be discussed here in detail. It is demonstrated that,at diameters of 1.5, 2.0 and 2.5 mm, minimal values of the difference ininjected quantities are achieved in comparison to diameters of 1.0 and3.0 mm. Tests with different rotational speeds and load conditions, asthey occur most frequently during the operation of theinternal-combustion engine, show which diameter D₂ is finally the mostsuitable one.

The optimal diameter D₂ of the high-pressure lines 2 leading from thecommon inflow pipe 1 to the high-pressure storage devices 3 can bemathematically represented by the following condition:

D₂≈((4×(V_(E)+V_(L)))/cg₂×π×T_(ASP)))^(½)

wherein

V_(e) is the maximal injection volume per injection operation,

V_(L) is a control and leakage quantity per injection operation possiblyoccurring at the fuel injector,

cg₂ is a standard value for the fuel flow rate in the line,

T_(ASP) is the time duration for an operating cycle of theinternal-combustion engine; wherein the values for V_(E), V_(L) andT_(ASP) are defined by the layout of the internal-combustion engine, andcg₂ is to amount to between 5 and 50 m/s. In the case of long thinlines, the value for cg₂ is between 5 and 25 m/s, and preferably between7 and 9 m/s. In the case of very short high-pressure lines 2, which inthe extreme case represent throttle-type transitions or in the case ofhigh-pressure lines 2 with throttle-type constrictions, a value for cg₂in the area of the narrow points is assumed to be between 10 and 50 m/s,preferably between 35 and 45 m/s.

The significant influence of the diameter D₂ of the high-pressure lines2 on the difference in the quantities injected by the individual fuelinjectors can be explained by a strong damping of the returning pressurewaves occurring during the opening and closing of the fuel injectors 5in the high-pressure lines, by means of which pressure waves a mutualinfluencing of the individual high-pressure storage devices 3 and thusof the fuel quantities emitted by these high-pressure storage devices 3to the fuel injectors 5 can be kept very low without additionalmeasures, for example, by means of return valves or throttles.

The diameter D₄ of the high-pressure lines 4 leading from thehigh-pressure storage devices 3 to the fuel injectors 5 should be solarge that the flow rate cg₄ of the fuel in these high-pressure linesduring the injection operation should be no higher than 30 m/s,preferably no higher than 25 m/s, in order to avoid excessive pressurelosses. Mathematically, this means that the diameter D₄ of thehigh-pressure lines 4 leading from the high-pressure storage devices 3to the fuel injectors 5 meets the following requirement:

D₄≧((4×V_(E))/(cg₄×π×SD))^(½)

wherein

V_(E) is the maximal injection volume per injection operation,

cg₄ is the permissible maximal flow rate of the fuel in the highpressure line 4, and

SD is the duration of the injection operation.

In contrast to the fuel injection system with a common high-pressurestorage device in the form of a common rail, in the case of the fuelinjection system according to the invention, the common inflow pipe 1 isnot used as a pressure storage device but only for filling the separatehigh-pressure storage devices 3 provided in the high-pressure lines 2, 4leading from the common inflow pipe 1 to the fuel injectors 5. Thefollowing applies to the diameter D₁ of the common inlet pipe 1 and thediameter D₂ of the high-pressure lines 2 leading from the common inletpipe 1 to the high-pressure storage devices 3:

D₁ ≧n _(R) ^(½)×D₂

wherein n_(R) is the number of fuel injectors 5 connected to the commoninlet pipe 1.

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

It is an important object of the invention to minimize as much aspossible the mutual influencing of the pressure in the individualhigh-pressure storage devices 3 without the use of additionalmass-incorporating and therefore sluggishly reacting components and toobtain a minimal difference in the injection quantities of the fuelinjectors 5. For this purpose, it is required that essentially the sameconditions apply to the individual fuel injectors 5 with respect totheir supply with fuel subjected to a high pressure. In addition to anidentical layout of the high-pressure storage device 3, this is achievedin that the lengths of the high-pressure lines leading from the commoninflow pipe 1 to the high-pressure storage devices 3, as well as of thehigh-pressure lines 4 leading from the high-pressure storage devices 3to the fuel injectors 5 are identical. If, in another step, theflow-dynamical conditions in the common inflow pipe 1 are also takeninto account, the diameter and the length of the common inflow pipe 1and of the high-pressure lines 2 leading from the common inflow pipe 1to the high-pressure storage devices 3 are mutually coordinated suchthat the flow resistance of the high-pressure lines 2 and of theassigned portions of the common inflow pipe 1 is identical for all fuelinjectors 5.

What is claimed is:
 1. Fuel injection system for an internal-combustionengine, comprising: a plurality of fuel injectors for injecting fuelinto combustion spaces of the internal-combustion engine; ahigh-pressure pump which supplies the fuel injectors with fuel via acommon inflow pipe and high-pressure lines leading to the fuelinjectors; a plurality of high-pressure storage devices which have adefined fuel storage volume and are provided in the high-pressure linesleading to the fuel injectors, wherein the fuel storage volume of eachof the high-pressure storage devices is between 80 and 300 times amaximal injected quantity per injection operation, and wherein thediameter D₂ of the high-pressure lines leading from the common inflowpipe to the high-pressure storage devices is dimensioned to have apredetermined value such that these high-pressure lines impart athrottling effect on the fuel flowing there through to the high-pressurestorage devices and thereby minimize a difference in quantities of fuelinjected by the fuel injectors.
 2. Fuel injection system according toclaim 1, wherein said fuel storage volume of each of the high-pressurestorage devices is between 120 and 200 times the maximal injectedquantity per injection operation.
 3. Fuel injection system according toclaim 1, wherein the diameter D₂ of the high-pressure lines leading fromthe common inflow pipe to the high-pressure storage devices meets therequirement: D₂≈((4×(V_(E)+V_(L)))/cg₂×π×T_(ASP)))^(½) wherein V_(E) isthe maximal injection volume per injection operation, V_(L) is a controland leakage quantity per injection operation occurring at the fuelinjector, cg₂ is a standard value for the fuel flow rate in the line,T_(ASP) is the time duration for an operating cycle of theinternal-combustion engine, wherein the values for V_(E), V_(L) andT_(ASP) are defined by the layout of the internal-combustion engine, andcg₂ is between 5 and 50 m/s.
 4. Fuel injection system according to claim1, wherein cg₂ is a value for fuel flow rate in said high-pressurelines, and wherein said high-pressure lines are relatively long and thinsuch that the value of cg₂ is between 5 and 25 m/s.
 5. Fuel injectionsystem according to claim 4, wherein the value of cg₂ is between ₇ and 9m/s.
 6. Fuel injection system according to claim 1, wherein cq₂ is avalue for fuel flow rate in said high-pressure lines, and whereinthrottle-type constrictions are present in at least one of saidhigh-pressure lines and an area between the inflow pipe and thehigh-pressure lines, and the value of cg₂ at said throttle-typeconstrictions is between 10 and 50 m/s.
 7. Fuel injection systemaccording to claim 6, wherein the value of cg₂ at said throttle-typeconstrictions is between 35 and 45 m/s.
 8. Fuel injection systemaccording to claim 1, wherein the diameter D₄ of the high-pressure linesleading from the high-pressure storage devices to the fuel injectors isdimensioned such that the flow rate cg₄ of the fuel in saidhigh-pressure lines during the injection operation is no higher than 30m/s.
 9. Fuel injection system according to claim 8, wherein the diameterD₄ of the high-pressure lines leading from the high-pressure storagedevices to the fuel injectors is dimensioned such that the flow rate cg₄of the fuel in said high-pressure lines during the injection operationis no higher than 25 m/s.
 10. Fuel injection system according to claim8, wherein the diameter D₄ of the high-pressure lines leading from thehigh-pressure storage devices to the fuel injectors meets therequirement: D₄≧(4×V_(E))/(cg₄×π×SD))^(½) wherein V_(E) is the maximalinjection volume per injection operation, cg₄ is the maximal permissibleflow rate of the fuel in the high-pressure line, and SD is the durationof the injection operation.
 11. Fuel injection system according to claim1, wherein the diameter D₁ of the common inflow pipe and the diameter D₂of the high-pressure lines leading from the common inlet pipe to thehigh-pressure storage devices meet the requirement: D₁ ≧n _(R) ^(½)×D₂wherein n_(R) is the number of fuel injectors connected to the commoninflow pipe.
 12. Fuel injection system according to claim 1, wherein thelengths of the high-pressure lines leading from the common inflow pipeto the high-pressure storage devices are identical.
 13. Fuel injectionsystem according to claim 10, wherein the diameter and the length of theinflow pipe and of the high-pressure lines leading from the commoninflow pipe to the high-pressure storage devices are mutuallycoordinated such that the dynamic flow resistance of the inflow pipes isidentical for all of the fuel injectors.
 14. A method of making a fuelinjection system for an internal combustion engine which includes: aplurality of fuel injectors for injecting fuel into combustion spaces ofthe internal-combustion engine; a high-pressure pump which supplies thefuel injectors with fuel via a common inflow pipe and high-pressurelines leading to the fuel injectors; and a plurality of high-pressurestorage devices which have a defined fuel storage volume and areprovided in the high-pressure lines leading to the fuel injectors, saidmethod comprising: designing the high-pressure storage devices so as tohave a fuel storage volume of between 80 and 300 times a maximalinjected quantity per injection operation of the fuel injectors, anddetermining the diameter D₂ of the high-pressure lines leading from thecommon inflow pipe to the high-pressure storage devices such that theyimpart a throttling effect on fuel flowing there through and therebyminimize differences in quantities of fuel injected by the fuelinjectors during engine operations.
 15. A method of making a fuelinjection system according to claim 23, wherein the diameter D₂ of thehigh-pressure lines leading from the common inflow pipe to thehigh-pressure storage devices meets the requirement:D₂≈((4×(V_(E)+V_(L)))/cg₂×π×T_(ASP)))^(½) wherein V_(E) is the maximalinjection volume per injection operation, V_(L) is a control and leakagequantity per injection operation occurring at the fuel injector, cg₂ isa standard value for the fuel flow rate in the line, T_(ASP) is the timeduration for an operating cycle of the internal-combustion engine,wherein the values for V_(E), V_(L) and T_(ASP) are defined by thelayout of the internal-combustion engine, and cg₂ is between 5 and 50m/s.
 16. A method of making a fuel injection system according to claim14, wherein cg₂ is a value for fuel flow rate in said high-pressurelines, and wherein said high-pressure lines are relatively long and thinsuch that the value of cg₂ is between 5 and 25 m/s.
 17. A method ofmaking a fuel injection system according to claim 16, wherein the valueof cg₂ is between 7 and 9 m/s.
 18. A method of making a fuel injectionsystem according to claim 14, wherein cg₂ is a value for fuel flow ratein said high-pressure lines, and wherein throttle-type constrictions arepresent in at least one of said high-pressure lines and an area betweenthe inflow pipe and the high-pressure lines, and the value of cg₂ atsaid throttle-type constrictions is between 10 and 50 m/s.
 19. A methodof making a fuel injection system according to claim 18, wherein thevalue of cg₂ at said throttle-type constrictions is between 35 and 45m/s.
 20. A method of making a fuel injection system according to claim14, wherein the diameter D₄ of the high-pressure lines leading from thehigh-pressure storage devices to the fuel injectors is dimensioned suchthat the flow rate cg₄ of the fuel in said high-pressure lines duringthe injection operation is no higher than 30 m/s.
 21. A method of makinga fuel injection system according to claim 20, wherein the diameter D₄of the high-pressure lines leading from the high-pressure storagedevices to the fuel injectors is dimensioned such that the flow rate cg₄of the fuel in said high-pressure lines during the injection operationis no higher than 25 m/s.
 22. A method of making a fuel injection systemaccording to claim 20, wherein the diameter D₄ of the high-pressurelines leading from the high-pressure storage devices to the fuelinjectors meets the requirement: D₄≧((4×V_(E))/(cg₄×π×SD))^(½) whereinV_(E) is the maximal injection volume per injection operation, cg₄ isthe maximal permissible flow rate of the fuel in the high-pressure line,and SD is the duration of the injection operation.
 23. A method ofmaking a fuel injection system according to claim 14, wherein thediameter D₁ of the common inflow pipe and the diameter D₂ of thehigh-pressure lines leading from the common inlet pipe to thehigh-pressure storage devices meet the requirement: D₁ ≧n _(R) ^(½)×D₂wherein n_(R) is the number of fuel injectors connected to the commoninflow pipe.
 24. A method of making a fuel injection system according toclaim 14, wherein the lengths of the high-pressure lines leading fromthe common inflow pipe to the high-pressure storage devices areidentical.
 25. A method of making a fuel injection system according toclaim 14, wherein the diameter and the length of the inflow pipe and ofthe high-pressure lines leading from the common inflow pipe to thehigh-pressure storage devices are mutually coordinated such that thedynamic flow resistance of the inflow pipes is identical for all of thefuel injectors.